Composite material with dielectric properties and preparation method thereof

Abstract

Techniques are generally described related to a composite material with dielectric properties and the preparation method thereof. One example composite material may include a core having a first polymer and an ionic salt and a shell having a second polymer, where the core is electrically conductive and the shell electrically insulates and substantially surrounds the core, wherein the first polymer has a first polarity and the second polymer has a second polarity, and the first polarity is greater than the second polarity.

We claim: 
     
       1. A composite material, comprising:
 a core comprising a first polymer and an ionic salt, wherein the first polymer comprises a fluoropolymer, and wherein the core is electrically conductive; and 
 a shell comprising a second polymer, wherein the second polymer comprises polyurethane, and wherein the shell electrically insulates and substantially surrounds the core, 
 wherein the first polymer has a first polarity and the second polymer has a second polarity, and the first polarity is greater than the second polarity. 
 
     
     
       2. The composite material of  claim 1 , wherein the composite material has a dielectric constant greater than 10,000. 
     
     
       3. The composite material of  claim 1 , wherein the first polymer and the ionic salt form a complex. 
     
     
       4. The composite material of  claim 1 , wherein the second polymer and the ionic salt do not form a complex. 
     
     
       5. The composite material of  claim 1 , wherein the first polymer comprises an atom selected from the group consisting of fluorine, oxygen, nitrogen, or a combination thereof. 
     
     
       6. The composite material of  claim 5 , wherein the atom is covalently bound to a carbon atom. 
     
     
       7. The composite material of  claim 1 , wherein the fluoropolymer is selected from the group consisting of polyethylene fluoride, polyvinylidene fluoride, polyethylene hexafluoropropylene, polychlorotrifluoroethylene, and copolymers thereof. 
     
     
       8. The composite material of  claim 1 , wherein the composite material has a dielectric constant of at least about 10 4 . 
     
     
       9. The composite material of  claim 1 , wherein the ionic salt is selected from the group consisting of sodium chloride, sodium nitrate, sodium phosphate, potassium chloride, lithium chloride, lithium perchlorate, lithium tetrafluoroborate, and lithium hexafluoropropene. 
     
     
       10. The composite material of  claim 1 , wherein the composite material is a film. 
     
     
       11. The composite material of  claim 10 , wherein the film has a dielectric constant of about 10 4  to about 10 7 . 
     
     
       12. The composite material of  claim 10 , wherein the film is a composite polymeric film. 
     
     
       13. The composite material of  claim 1 , wherein a mass ratio of the first polymer to the second polymer is about 0.5 to about 2. 
     
     
       14. The composite material of  claim 1 , wherein a mass ratio of the first polymer to the ionic salt is about 1 to about 10. 
     
     
       15. A film, comprising:
 a core comprising a first polymer and an ionic salt, wherein the first polymer comprises a fluoropolymer, and wherein the core is electrically conductive; and 
 a shell comprising a second polymer, wherein the second polymer comprises polyurethane, and wherein the shell electrically insulates and substantially surrounds the core, 
 wherein the first polymer has a first polarity and the second polymer has a second polarity, and the first polarity is greater than the second polarity. 
 
     
     
       16. The film of  claim 15 , wherein the film has a dielectric constant of about 10 4  to about 10 7 . 
     
     
       17. The film of  claim 15 , wherein a mass ratio of the first polymer to the second polymer is about 0.5 to about 2. 
     
     
       18. The film of  claim 15 , wherein a mass ratio of the first polymer to the ionic salt is about 1 to about 10. 
     
     
       19. The film of  claim 15 , wherein the first polymer and the ionic salt form a first complex, and wherein the second polymer and the ionic salt do not form a second complex. 
     
     
       20. The film of  claim 15 , wherein the film has a dielectric constant greater than 10,000 when measured as frequency-dependent relative permittivity.